The present invention relates to improvements in or relating to hitch assemblies for connecting a trailer to a tow vehicle.
Vehicle trailers which may for example include caravans, domestic trailers, commercial trailers, water craft trailers and the like, which are normally connected to a vehicle such as a car or truck are well known. The most common form of coupling that is formed between the vehicle and its trailer is by the provision of a tow ball secured to a vehicle to which a female coupling member secured to the trailer (usually to the tow or draw bar of a trailer) can be secured. The female coupling member usually incorporates a displaceable portion which can be moved to a condition to allow for the female member to fall over the tow ball of the vehicle. The moveable member is then moved to a condition where it will subsequently prevent the female member from being uplifted from the tow ball.
The female member is usually located at the end of a draw bar which is rigidly fixed to the frame or chassis of the trailer. In order for the coupling between the vehicle and the trailer to be made, the tow ball of a vehicle must be placed in the vicinity or below the female member of the trailer.
The female member then needs to be manoeuvred, which normally requires the movement of the entire trailer so that it and the tow ball can be aligned for engagement. Although some trailers provide a jockey wheel on the draw bar to allow for the female member to be raised and lowered, normally there are no provisions to allow for the female coupling to be moved independently of the trailer. Therefore in order to make the coupling the entire trailer may need to be rotated and/or displaced to achieve the alignment.
Although this may not be a difficult task for smaller trailers or trailers where there is no significant loading, for caravans, boat trailers or other trailers where there is a significant resistance to movement, the achievement of a coupling between the trailer and the vehicle can be difficult. In such instances it is virtually essential for the tow ball of a vehicle to be located immediately below the female member of the trailer. An example of a means which allows for an increase in accuracy and simplicity of the placement of a tow ball of a vehicle is described in GB2247438. This patent specification describes a sighting device to assist the coupling of a trailer to a towing vehicle. The use of devices such as this still requires a driver of the vehicle to manoeuvre the tow ball to a position to allow an easy coupling to be achieved.
Devices to allow for a guided engagement of the trailer and the vehicle to be achieved are also known. In for example GB2170769, there is described the use of a coupling for towing vehicles which utilises an intermediate member between the securing means of the trailer with the tow ball of a vehicle. This intermediate member with the use of angled guide portions as part of the trailer allows for a vehicle to be backed towards a trailer and for the intermediate member to be guided to the trailer coupling.
Several patent specifications describe means by which an accurate positioning of the tow ball of a vehicle becomes in-essential.
GB225290 describes indeed an alternative arrangement to simplify the achievement of a coupling between a trailer and a vehicle. In this specification there is described a trailer coupling which by way of a cable connected to the trailer (preferably through the draw bar) can allow the trailer coupling to be positioned onto the tow bar of a vehicle and be subsequently winched by retracting the cable, to move the vehicle and trailer to a more proximate position to then allow the trailer coupling to be locked in place relative to the draw bar.
In U.S. Pat. No. 5277447 there is described a trailer coupling mechanism which consists of a telescopic and articulatable draw bar which allows for simplified alignment between the trailer coupling and its counterpart vehicle coupling.
The device is capable of both an axial and lateral movement and allows for a coupling between the trailer and the vehicle to be achieved as long as both coupling portions are within a region that can be reached by the movement of the device. Therefore it is not essential for a tow ball of a vehicle to be moved accurately as long as it is moved within the range of movement provided by the device.
Once the coupling has been made, the device still requires alignment of the portions to allow a retraction of these telescopic feature to be achieved to create a rigid draw bar arrangement.
It is therefore an object of the present invention to provide improvements in or relating to towing apparatus for trailers which will at least provide the public with a useful choice.
Accordingly in a first aspect the present invention consists a telescoping hitch assembly for connecting a trailer to a tow vehicle comprising:
a first member engaged or engagable to a trailer
a coupling arm telescopically engaged with said first member, said coupling arm adapted for coupling at or towards a first distal end thereof to said vehicle
a ratchet arrangement between said first member and said coupling arm , said arrangement including ratchet surface defining means and at least one movable deployable member engageable with said ratchet surface defining means
wherein said moveable deployable member is moveable between an operative condition(ratchet) and an inoperative (non ratchet) condition,
and wherein said deployable member, when in its operative condition, prevents displacement between said ratchet surface defining means and said deployable member in a direction of telescopic extension between said first member ands said coupling arm.
Preferably said first member carries said ratchet surface defining means.
Preferably said ratchet surface defining means is located within a cavity of said first member, and wherein said deployable member is moveably located within said cavity.
Preferably said ratchet surface defining means provides at least one ratchet surface of a plurality of reliefs being of a shape to allow engagement of a ratchet kind therewith by said deployable member.
Preferably said surface of said ratchet surface defining means is of an inclined stepped nature.
Preferably said ratchet surface defining means is dependably located from said first member and said deployable member carried by and is pivotally connected to said coupling arm within said cavity to pivot between said operative (ratchet surface defining means engaged) an inoperative conditions.
Preferably said deployable member in operative condition is engaged with a relief of the ratchet surface defining means to prevent telescopic extension but allow retraction of the connection arm to said ratchet surface defining means and
in said inoperative condition is pivoted away from being engaged with the ratchet surface defining means to allow axial displacement between said ratchet surface defining means and the coupling arm.
Preferably said first member is a hollow rigid elongate member.
Preferably said ratchet surface defining means is axially (in the telescopic direction) displaceable relative to said first member within inner (in direction of retraction) and outer (in direction of extension) limits.
Preferably said inner and outer limits are defined by end stops of said cavity of said first member.
Preferably said ratchet surface defining means is biased away from at least one of said inner or outer limits by biasing means.
Preferably said ratchet surface defining means is biased away from both said inner and outer limits by biasing means.
Preferably said biasing means are springs.
Alternatively said ratchet surface defining means is fixed relative to said first member.
Preferably said ratchet surface defining means is of a xe2x80x9cUxe2x80x9d section, having at least one inwardly directed ratchet surface.
Preferably said section provides two opposite and inwardly facing ratchet surfaces.
Preferably there are two deployable members pivotally connected to the coupling arm, each moveable to and from said operative and inoperative conditions in opposite directions.
Preferably said coupling arm is substantially elongate and is adapted at one distal end for coupling to said vehicle by a means engagable to a connection point of a vehicle.
Preferably said means engagable is a female coupling member engagable to a tow ball connection point of a vehicle.
Preferably at the other distal end of said coupling arm is provided the at least one deployable member.
Preferably said telescopic engagement of said first member and coupling arm is such that the coupling arm moves in part in and out and from one end of the first member.
Preferably said at least one deployable member is actuatable between is operative and inoperative conditions by a manually actuable means.
Preferably said manually actuable means is a lever pivotally connected to said coupling arm about an axis normal to the telescopic axis, and actuates a push rod coaxial with said coupling arm between two limits of movement defined by positions in which said at least one deployable member is in its operative and inoperative conditions wherein movement from one limit to the other, positively displaces the at least one deployable member to an inoperative condition.
Preferably said at least one deployable member is biased towards its operative condition by a biasing means.
In a second aspect the present invention consist in a rotatable hitch assembly for connecting a trailer to a tow vehicle comprising:
a base member engaged or engagable to a trailer
a second member to or from which a coupling arm adapted to connect to the vehicle extends, said second member rotatably engaged about a vertical axis of rotation with said base member,
at least one means to lock, rotatably carried by one of said base or second members and held in a sliding engagement with the other of said base or second member save for at one locking position where the base and second members are in a desired relative angular disposition, wherein said means to lock refrains relative rotation of said base and second members.
Preferably said means to lock acts between two concentrically moving parts of said base and second member.
Preferably said means to lock is carried by said second member and is displaceable thereto to locate at leas in part with a recess of a concentric surface of said base member when in said desired relative angular disposition.
Preferably said means to lock is a lug displaceable in a radially outward direction to said second member when in an aligned condition with said recess.
Preferably said desired angular disposition of said base and second members is when the plane through the axis of rotation in the alignment with the point of connection of said second is parallel to the direction alignment of the wheels of the trailer.
Preferably said concentric surface allows the said lug to rotate there over save for when aligned with said recess.
Preferably a cam plate is provided which is actuably rotatable about said axis of rotation relative to said second member, said cam plate being provided with a camming surface with which a cam follower of said lug acts,where upon rotation of the cam plate relative to the said second member, said lug is thereby moved at least from its locking condition to an unlocking condition.
Preferably said lug is biased to act in a direction to lock.
Preferably said biasing of said lug is by a spring.
Preferably two pawls are provided to act between said base and second member each operative in opposite directions of rotation in preventing rotation of said locking means away from said desired angular disposition.
Preferably said pawls are pivotably rotatable about pivot points to the second member and each extend to locate with an inwardly directed surface of said base member, wherein said surface is provided with reliefs which act with said pawls to prevent rotation of said locking member away from said recess.
Preferably said pawls are pivotably rotatable to the second member and each extend to locate with an inwardly directed surface of said base member, wherein said surface is provided with reliefs, where that pawl to prevent rotation in the direction away from said desired angular disposition is that pawl which extends in that direction of rotation from it pivot point to said second member.
Preferably said cam plate also has cam surfaces for engagement by cam followers of said pawls whereby the pawls can upon the rotation of said cam plate be retracted from said surface of said base member.
Preferably said rotation of said cam plate to move said lug from its locking condition also simultaneously moves the pawls from said surface.
In another aspect the present invention consist in a rotatable hitch assembly for connecting a trailer to a tow vehicle comprising:
a base member engaged or engagable to a trailer
a second member to or from which a coupling arm adapted to connect to the vehicle extends, said second member rotatably engaged about a vertical axis of rotation with said base member,
a rotatable ratchet arrangement between said base and second members said arrangement including
a ratchet surface,
a first ratchet surface engagable means and a second ratchet surface engagable means, each operative with said ratchet surface in preventing relative rotation between said base and second members in one and opposite directions only.
In a further aspect the present invention consists in hitch assembly for connecting a trailer to a tow vehicle, wherein the hitch assembly is of rotatable and telescopic kind as herein described.
This invention may also be said broadly to consist in the parts, elements and features referred to or indicated in the specification of the application, individually or collectively, and any or all combinations of any two or more of said parts, elements or features, and where specific integers are mentioned herein which have known equivalents in the art to which this invention relates, such known equivalents are deemed to be incorporated herein as if individually set forth.
The invention consists in the foregoing and also envisages constructions of which the following gives examples.